4bbl Slant Intake

Clifford and offie intake flanges are the same thickness. Clifford headers have the same thickness flange as the intakes. Hooker header flanges are thinner, and need a button or nut welded on to make up the thickness. Aussie Speed header flanges are thinner, but have "buttons" welded on to make up the difference. The old mopar performance 6-1 headers (made by JR) may or may not have nuts welded to the flange. I have one of each.